[WebLayer] Add GmsBridge upstream classes and the relevant build configs

In this patch:

- add the abstract GmsBridge class and its corresponsing upstream
  implementation (GmsBridgeImpl.java). GmsBridge class manages
  functionality related to Google Mobile Services (GMS).

- add the initialization of safebrowsing handler on WebLayer startup.

- add .gn build deps and targets needed for the relevant upstream
  targets. In the future a different GmsBridgeImpl class will be
  compiled-in depending on whether an internal clank/ checkout
  is present.

BUG=1015418

Change-Id: I5a45023a0ab6f31ce6db1daa7f62bf7c2579a84b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1876032Reviewed-by: Richard Coles <torne@chromium.org>
Commit-Queue: Tim Volodine <timvolodine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709447}

weblayer/browser/java/BUILD.gn

@@ -38,6 +38,7 @@ android_library("java") {
 
   deps = [
     ":client_java",
+    ":gms_bridge_java",
     ":weblayer_resources",
     "//base:base_java",
     "//base:jni_java",
@@ -50,6 +51,10 @@ android_library("java") {
   srcjar_deps = [ ":weblayer_locale_config" ]
   jar_excluded_patterns = [ "*/LocaleConfig.class" ]
   annotation_processor_deps = [ "//base/android/jni_generator:jni_processor" ]
+
+  # TODO(timvolodine): once the downstream implementation of GmsBridgeImpl.java
+  # lands make sure to exclude this when "enable_chrome_android_internal" is true.
+  deps += [ ":gms_bridge_upstream_impl_java" ]
 }
 
 generate_jni("jni") {
@@ -77,6 +82,32 @@ android_library("client_java") {
   srcjar_deps = [ ":aidl" ]
 }
 
+# Separate target to allow for a dependency on GmsCore without pulling in all of
+# java classes. It compiles the abstract class; implementations are compiled
+# separately.
+android_library("gms_bridge_java") {
+  java_files = [
+    "org/chromium/weblayer_private/GmsBridge.java",
+    "org/chromium/weblayer_private/GmsBridgeImpl.java",
+  ]
+
+  deps = [
+    "//base:base_java",
+  ]
+
+  # The appropriate .class file will be loaded via a dependency to a library
+  # like :gms_bridge_upstream_impl_java below.
+  jar_excluded_patterns = [ "*/GmsBridgeImpl.class" ]
+}
+
+# This target compiles the implementation of GmsBridge for public targets.
+android_library("gms_bridge_upstream_impl_java") {
+  java_files = [ "org/chromium/weblayer_private/GmsBridgeImpl.java" ]
+  deps = [
+    ":gms_bridge_java",
+  ]
+}
+
 android_aidl("aidl") {
   import_include = [ "org/chromium/weblayer_private/aidl" ]
   sources = [

weblayer/browser/java/org/chromium/weblayer_private/GmsBridge.java

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.weblayer_private;
+
+import android.os.Handler;
+import android.os.HandlerThread;
+
+/**
+ * This class manages functionality related to Google Mobile Services (i.e. GMS).
+ * Platform specific implementations are provided in GmsBridgeImpl.java.
+ */
+public abstract class GmsBridge {
+    private static GmsBridge sInstance;
+    private static final Object sInstanceLock = new Object();
+
+    private static HandlerThread sHandlerThread;
+    private static Handler sHandler;
+    private static final Object sHandlerLock = new Object();
+
+    protected GmsBridge() {}
+
+    public static GmsBridge getInstance() {
+        synchronized (sInstanceLock) {
+            if (sInstance == null) {
+                // Load an instance of GmsBridgeImpl. Because this can change depending on
+                // the GN configuration, this may not be the GmsBridgeImpl defined upstream.
+                sInstance = new GmsBridgeImpl();
+            }
+            return sInstance;
+        }
+    }
+
+    // Return a handler appropriate for executing blocking Platform Service tasks.
+    public static Handler getHandler() {
+        synchronized (sHandlerLock) {
+            if (sHandler == null) {
+                sHandlerThread = new HandlerThread("GmsBridgeHandlerThread");
+                sHandlerThread.start();
+                sHandler = new Handler(sHandlerThread.getLooper());
+            }
+        }
+        return sHandler;
+    }
+
+    // Returns true if the WebLayer can use Google Mobile Services (GMS).
+    public boolean canUseGms() {
+        return false;
+    }
+
+    public void setSafeBrowsingHandler() {
+        // We don't have this specialized service here.
+    }
+}
\ No newline at end of file

weblayer/browser/java/org/chromium/weblayer_private/GmsBridgeImpl.java

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.weblayer_private;
+
+/**
+ * Instantiable version of {@link GmsBridge}, don't add anything to this class!
+ * Downstream targets may provide a different implementation.
+ */
+public class GmsBridgeImpl extends GmsBridge {}

weblayer/browser/java/org/chromium/weblayer_private/OWNERS

+# For safebrowsing related files
+per-file *GmsBridge*=timvolodine@chromium.org

weblayer/browser/java/org/chromium/weblayer_private/WebLayerImpl.java

@@ -104,6 +104,7 @@ public final class WebLayerImpl extends IWebLayer.Stub {
         ContentUriUtils.setFileProviderUtil(new FileProviderHelper());
 
         LibraryLoader.getInstance().ensureInitialized(LibraryProcessType.PROCESS_WEBLAYER);
+        GmsBridge.getInstance().setSafeBrowsingHandler();
 
         final ValueCallback<Boolean> loadedCallback = (ValueCallback<Boolean>) ObjectWrapper.unwrap(
                 loadedCallbackWrapper, ValueCallback.class);